The present invention relates to an air filter enclosure of the type useable for filtering the intake air of an internal combustion engine. In particular, the present invention relates to an air filter housing assembled from multiple portions and an arrangement for fastening the portions at their periphery to form the housing.
In general, prior structures for fastening the portions of air filter housings together and secure a seal therebetween include over-center catches constructed of steel wire or a metal stamping, metal screws, nuts and torque limiting fasteners. These structures were typically equally spaced around the joint between the housing portions to fasten the portions together. This spacing was used in an attempt to provide a generally uniform pressure on the seal between the portions to avoid air leakage at locations which would permit unfiltered air to enter the intake of the associated engine.
A problem with over-center catches is the inability to economically manufacture housing portions which apply adequate pressure to the seal without warping and producing unwanted leakage of unfiltered air into the associated engine. Another problem with over-center catches is the complexity of the mold required to produce the latching surfaces (i.e. undercuts which make plastic part removal from a mold difficult) on the housing portions which are engaged by the catch. Furthermore, many catches presently used for the above-described purpose are difficult to open by hand.
A problem with the use of combinations of screws, bolts, nuts and wing nuts for fastening housing portions together is the inability to insure application or relatively consistent torque to all of the screws, bolts, nuts or wing nuts holding the housing portions together. Without relatively consistent torques and/or the complete absence of a fastener, the housing may warp and fail to provide a seal which prevents unwanted leakage of unfiltered air into the associated engine. Furthermore, metal fasteners may corrode over time and prevent disassembly of the portions of a filter housing by hand and without the use of tools.
In view of the problems inherent with presently available arrangements for joining the portions of a filter housing, it would be desirable to provide an arrangement for joining the portions of a filter housing which is efficiently molded from an appropriate material such as plastic, easy to handle and not easily dropped or lost in a relatively inaccessible portion of the engine, easily engaged with the housing portions when fastening the portions together, easily removed from the housing portions to permit filter replacement, and configured to force the housing portions together at the seal therebetween to provide relatively uniform pressure on the seal.